Linux之正则表达式与文件格式化处理

正则表达式主要是用在对字符串进行处理。注意一点的是正则表达式与通配符是完全不一样的东西，开机过程中的相关程序都在/etc/init.d

1.grep详解

grep最重要的功能就是进行数据比对时，然后将符合要求的字符串打印出来，注意grep在数据查找时，是以一个“整行”为单位来进行数据获取的
以下面这个文本为例子解释grep。

"Open Source" is a good mechanism to develop programs.apple is my favorite food.Football game is not use feet only.this dress doesn't fit me.However, this dress is about $ 3183 dollars.GNU is free air not free beer.Her hair is very beauty.I can't finish the test.Oh! The soup taste good.motorcycle is cheap than car.This window is clear.the symbol '*' is represented as start.Oh! My god!The gd software is a library for drafting programs.You are the best is mean you are the no. 1.The world <Happy> is the same with "glad".I like dog.google is the best tools for search keyword.goooooogle yes!go! go! Let's go.# I am VBird

1. 搜索特定字符串
   搜索带有’the’
   
   反向搜索，搜索没有’the’的
   
   要取得部分大小写的’the’字符串
   
2. 利用中括号[]来搜索集合字符
   
   如果要搜索带有’oo’的字符
   
   
   我想’oo’字符前没有小写字母
   
   要取有数字的一行
   
   也可以这样
   
   423